INDUCED-GRATING AUTOCORRELATION OF ULTRASHORT PULSES IN A SLOWLY RESPONDING MEDIUM

We consider induced-grating autocorrelation (IGA) in a slowly responding medium and study three possible geometries (two-beam coupling, three-beam induced grating, and self-diffraction) in two different limiting cases (single-pulse experiments and many-pulse accumulated-grating experiments). We find that in five of these six cases the IGA trace is given by the squared amplitude of the electric-field correlation function, thus yielding information about the spectrum of the pulse. Theoretical expressions for the IGA trace are derived for both linearly chirped and self-phase-modulated pulses. Experiments performed with self-phase-modulated pulses are in excellent agreement with the theory. In this case we show how the measured IGA trace can be used to determine both pulse duration and pulse bandwidth.